P0270 on 2009-2014 Chevrolet Traverse: Cylinder 4 Injector Circuit Low Causes and Fixes

What's Unique About the 2009-2014 Chevrolet TRAVERSE

For this generation of the Chevrolet Traverse and its platform mates (like the GMC Acadia, Buick Enclave, and Saturn Outlook) equipped with the 3.6L V6 engine, P0270 is frequently not a faulty injector. General Motors issued a specific Technical Service Bulletin (TSB #PIP4924D) highlighting that the fuel injector wiring harness is prone to chafing and developing shorts or opens. Specific chafe points mentioned by GM are against the intake plenum, at valve cover bolts, against the fuel line, and on the side of the cylinder head under the plenum. This makes a wiring inspection the critical first step, as opposed to immediately suspecting the injector itself.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Rough or shaking idle
• Engine hesitation or stumbling during acceleration
• Noticeable loss of engine power
• Reduced fuel economy
• A flashing Check Engine Light during severe misfires
• Engine may stall intermittently

Most Likely Causes

1. Fuel Injector Wiring Harness Chafing or Damage 🔴 High Probability As documented in GM TSB #PIP4924D, the harness routing can cause it to rub against engine components. Specific chafe points are the intake plenum, valve cover bolts, fuel lines, and the side of the cylinder head. Engine vibration over many miles wears through the wire insulation, causing a short to ground or an open circuit.
   How to confirm: Visually inspect the entire fuel injector harness, especially the Bank 2 (front) harness branch. Pay close attention to the areas mentioned in the TSB. Look for rubbed-through insulation, exposed copper wires, or sharp bends. Use a multimeter to check for a short to ground or an open circuit on both wires (power and control) leading to the cylinder 4 injector connector.
   Typical fix: Repair the damaged section of wire using a weatherproof butt connector and heat shrink tubing. If damage is at the connector, splice in a new pigtail connector (e.g., ACDelco PT2160). After repair, secure the harness away from the sharp edge or vibration point using zip ties or re-routing to prevent recurrence.
   Est. part cost: $15-$60
2. Faulty Cylinder 4 Fuel Injector 🟡 Medium Probability The direct injection (DI) injectors on both the LLT and LFX engines operate under high pressure and heat inside the combustion chamber, which can lead to internal electronic failure or clogging over time.
   How to confirm: After confirming the wiring is good, swap the cylinder 4 fuel injector with one from another cylinder (e.g., cylinder 2, the front-most cylinder). Clear the codes and run the engine. If the code changes to P0264 (Cylinder 2 Injector Circuit Low), the injector is faulty. If P0270 returns, the problem is not the injector. An injector resistance test can also be performed; compare the Ohm reading to the manufacturer's specification. A typical resistance for these GDI injectors is between 1.5 and 2.5 ohms.
   Typical fix: Replace the faulty fuel injector. It is highly recommended to replace the Teflon seal and o-ring on the new injector. For direct injection, it's often advised to replace all injectors on the same bank (Bank 2: cylinders 2, 4, 6) at the same time.
   Est. part cost: $70-$150
3. Dirty or Damaged Injector Connector ⚪ Low Probability
   How to confirm: Unplug the connector at the cylinder 4 fuel injector and inspect the terminals for corrosion, moisture, bent/loose pins, or heat damage. Ensure it clicks securely into place and the locking tab is not broken.
   Typical fix: Clean the connector terminals with electrical contact cleaner. If the connector housing is damaged or pins are loose, replace it with a new pigtail connector.
   Est. part cost: $15-$40

Rare But Worth Checking

• Faulty Engine Control Module (ECM): This is the least likely cause. The ECM's internal driver for the injector circuit can fail, but all other possibilities, especially wiring, must be exhaustively ruled out first before condemning the ECM. Multiple injector circuit codes appearing at once (e.g., P0270, P0264, P0261) can point towards a widespread harness issue or a failing ECM driver bank.

Diagnosis Steps

1. Read all fault codes with an OBD-II scanner. Note if P0304 (Cylinder 4 Misfire) or other injector codes are present.
2. Locate Cylinder 4: On the transverse 3.6L V6, the cylinders against the firewall are Bank 1 (odd: 1, 3, 5). The cylinders near the radiator are Bank 2 (even: 2, 4, 6). Cylinder 4 is the middle cylinder on the front (radiator side) bank.
3. Perform a Detailed Wiring Inspection: As recommended by TSB #PIP4924D, meticulously inspect the fuel injector wiring harness. Key chafe points are where the harness touches the intake plenum, valve cover bolts, metal fuel lines, and the side of the cylinder head. Flex and move the harness to reveal hidden damage.
4. Inspect the Connector: Unplug the electrical connector at the cylinder 4 fuel injector. Check for corrosion, bent pins, or a loose fit.
5. Perform a 'Noid Light' Test: Connect a noid light to the cylinder 4 injector harness connector. Start the engine. The light should flash steadily, indicating the ECM is sending a pulse signal. If there is no pulse or a weak pulse, the issue is in the wiring or the ECM.
6. Test Injector Resistance: With the injector unplugged, use a multimeter to measure the resistance across its two pins. Compare the reading to the manufacturer's specification (typically 1.5-2.5 ohms for these DI injectors 🎬 Watch: Deep dive into 3.6L injector resistance and circuit testing.). An open circuit (infinite resistance) or a dead short (zero resistance) indicates a failed injector.
7. Swap Injectors: If wiring and signal are confirmed good, swap the cylinder 4 injector with an injector from a different cylinder (e.g., cylinder 2). Clear the codes. If the fault moves to P0264 (Cylinder 2), the injector is bad. If P0270 returns, the problem is in the wiring or ECM.
8. Final ECM Check: If the injector is good and the code remains on cylinder 4, the fault is almost certainly in the wiring harness. A pin-to-pin continuity test from the injector connector to the ECM connector is the final confirmation. Only if the wiring is proven to be perfect should the ECM be considered faulty.

Parts You'll Likely Need

• Fuel Injector Wiring Harness Pigtail (OEM #ACDelco PT2160 / GM 13584094 (PT2712)) — This is needed to repair the damaged connector or a small section of wiring near the injector, which is a common failure point due to heat and vibration.
  Trusted brands: ACDelco, Standard Motor Products (S-824), Dorman
  OEM price range: $25-$50
  Aftermarket price range: $15-$30
• Fuel Injector (OEM #12634126 (LFX, 2012+), 12669384 or 12632255 (LLT, 2009-2011)) — If the injector itself has failed internally (shorted coil), it will need to be replaced. Part numbers differ between the LLT and LFX engines.
  Trusted brands: ACDelco (OEM), Bosch, Hitachi, GB Remanufacturing
  OEM price range: $100-$150
  Aftermarket price range: $60-$90
• Engine Wiring Harness (OEM #12621095) — In rare cases of extensive, non-repairable damage to the injector harness, the entire engine harness assembly may need replacement.
  Trusted brands: GM Genuine Parts
  OEM price range: $400-$600

Related Codes That Often Appear With This One

• P0304 — This code means 'Cylinder 4 Misfire Detected'. P0270 causes a fuel delivery problem in cylinder 4, which directly results in a misfire.
• P0261, P0264, P0267, P0273, P0276 — These are injector circuit low codes for other cylinders. If multiple injector codes are present simultaneously, it strongly indicates a widespread wiring harness issue (as described in TSB #PIP4924D) or a failing ECM.

Technical Service Bulletins (TSBs) & Recalls

• PIP4924D: This is the primary document for this issue. It instructs technicians to inspect the fuel injector wiring harness for chafing against the intake plenum, valve cover bolts, fuel lines, and cylinder head when encountering various injector circuit codes, including P0270. It applies to a wide range of GM vehicles with the 3.0L and 3.6L V6 engines.

Platform-Specific Known Issues

• GM Technical Service Bulletin #PIP4924D explicitly calls out that the fuel injector wiring harness can rub through against various engine components, causing shorts or open circuits that trigger injector codes like P0270.
• Owners on forums frequently report finding the injector harness chafed near the front (Bank 2) valve cover or where it passes by the intake manifold.
• The location of Cylinder 4 (front bank, middle cylinder) makes it and its wiring susceptible to damage during other engine repairs if care is not taken.

Mechanic-Grade Diagnostic Values

• Fuel Injector Coil Resistance — expected: 1.5 to 2.5 Ohms on a good injector. Some sources state a broader range of 2-18 Ohms is acceptable, but vehicle-specific tests show 1.5-1.6 Ohms is common.. Failure: A reading of infinite resistance (open circuit) or near-zero resistance (short circuit).
• Injector Circuit Control Wire Voltage (at ECM) — expected: Near battery voltage when the injector is OFF, near zero volts when the injector is commanded ON (pulsing).. Failure: Voltage that is consistently low or zero when it should be high indicates a short to ground in the harness. Voltage that does not drop when commanded ON indicates an open circuit or bad ECM driver.
• GDS2 Injector Balance Test — expected: The pressure drop for each injector should be within 20% of the average pressure drop of the other injectors.. Failure: A cylinder with a pressure drop significantly less or more than the others indicates a flow problem (clogged or leaking injector).

Scan Tool Commands That Help

• GM GDS2 / Tech2 or equivalent professional scan tool: Injector Balance Test — This bidirectional command individually pulses each injector and measures the corresponding drop in fuel rail pressure. It is used to identify a mechanically faulty, clogged, or leaking injector that may not have an electrical fault. If P0270 is intermittent or if wiring checks out, this test can confirm if the injector is flowing fuel correctly compared to the others.
• GM GDS2 / Tech2 or equivalent professional scan tool: Cylinder Power Balance — This function disables one cylinder at a time and measures the drop in engine RPM. While primarily for misfire diagnosis (P0304), it can help confirm if the cylinder 4 circuit fault is causing a complete lack of combustion. If disabling cylinder 4 causes no change in RPM, it confirms it was not contributing power.

Wiring & Ground Locations

• Cylinder 4 Injector Wires (at ECM) — On the 3.6L LLT engine, the Cylinder 4 injector control wire (low side driver) is a Light Blue wire, and the high side driver wire is a Light Blue with White stripe. These are located at pins 50 and 74, respectively, of the X1 ECM connector.. These are the specific pins to test at the ECM for continuity back to the injector connector. A break or short on either of these wires will cause P0270.
• G101 / G106 — G101 is located on the lower front of the engine block. It is often jumpered to G106, which is on the front center of the frame cross rail, under the crank pulley.. G101 is a primary ground for the Engine Control Module (ECM) and Transmission Control Module (TCM). A poor connection here can cause erratic behavior and incorrect voltage readings for multiple sensors and actuators, including the injector driver circuits.
• G110 — Located at the right rear of the engine, mounted to the back of the cylinder head, sometimes on a bracket above the power steering pressure hose.. This is another critical engine ground. A loose or corroded G110 can cause a host of issues, including communication problems and intermittent faults that are hard to trace.

Real Owner Repair Stories

• traverseforum.com user (2011 Chevrolet Traverse LT) — Check engine light with codes P0270 and P0304 (Cylinder 4 misfire). Engine ran rough.
  ❌ Tried (didn't work) Initially suspected a bad fuel injector.
  ✅ What actually fixed it The user found the fuel injector wiring harness was chafed and shorting out against the engine block, exactly as described in TSB #PIP4924D. The repair involved fixing the damaged wires in the harness.

OEM Part Supersession History

• 12632255 / 12638530 → 12669384 — Standard part revision and improvement by the manufacturer for the LLT engine.
  Heads up: These part numbers are for the LLT engine and are NOT compatible with the 2012-2014 LFX engine, which uses different injectors.

Model Year Variations Within This Range

• 2009-2011: These models use the 3.6L LLT V6 engine. They have an aluminum intake manifold, separate exhaust manifolds, and use a Bosch ECM. The fuel injector part number was originally 12632255 or 12638530, later superseded by 12669384.
• 2012-2014: These models use the updated 3.6L LFX V6 engine. Key changes include a lighter composite intake manifold, cylinder heads with integrated exhaust manifolds, a Delphi ECM, and different fuel injectors (e.g., 12634126). The parts, particularly injectors, are not interchangeable with the earlier LLT engine.